Below is an example of how it's not always smart to just go for the first thing that comes to mind. You need to generally think about things for a bit before acting.

Read this article for a more in-depth understanding.

The best advice I’ve ever gotten about thinking came from a private-company CEO who has a thirty-year track record that’s up there with Warren Buffett’s. One day he said to me, “Shane, most people don’t actually think. They just take their first thought and go.”

The problem with not having time to think is nailed by William Deresiewicz, who said:

I find for myself that my first thought is never my best thought. My first thought is always someone else’s; it’s always what I’ve already heard about the subject, always the conventional wisdom.

Here’s what Deresiewicz says does work:

It’s only by concentrating, sticking to the question, being patient, and letting all the parts of my mind come into play, that I arrive at an original idea. By giving my brain a chance to make associations, draw connections, take me by surprise. And often even that idea doesn’t turn out to be very good. I need time to think about it, too, to make mistakes and recognize them, to make false starts and correct them, to outlast my impulses, to defeat my desire to declare the job done and move on to the next thing.